#include<stdio.h>
double calculator (char *ptr);
int main()
{
	int b=0;
	char x[100];
	double a;
	scanf("%s",&x);
	char *ptr=&x[0];
	calculator(ptr);
	return 0;
}
double calculator (char *ptr)
{
	for(int i=0;;i++)
	{
  	if((*(ptr+i)<='9'&&*(ptr+i)>='0')||*(ptr+i)=='+'||*(ptr+i)=='-'||*(ptr+i)=='*'||*(ptr+i)=='/')
  	    continue;
  	else if(*(ptr+i)==NULL)
  	break;
  	else{
  	    printf("Input Error\n");
  	    return 0;
        }
    }
	double result,x,y;
	char w;
    sscanf(ptr,"%lf%c%lf",&x,&w,&y);
    if(w=='+')
    result=x+y;
    else if(w=='-')
    result=x-y;
    else if(w=='*')
    result=x*y;
    else if(w=='/'&&y!=0)
    result=x/y;
	else if(w=='/'&&y==0){
	  printf("Input Error");
	  return 0;
	}
	printf ("%.2lf",result);
	return 0;
}

